Chickahominy Reservoir Reservoir Report

Last Updated: December 14, 2025

Chickahominy Reservoir, also known as Chickahominy Creek Dam, is a state-owned water resource located in Riley, Oregon.


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Summary

Built in 1951, this earth dam stands at 38 feet tall and stretches 300 feet in length, creating a storage capacity of 9,000 acre-feet for irrigation purposes. The reservoir covers a surface area of 529.4 acres and is fed by Chickahominy Creek, with a maximum discharge capacity of 2,862 cubic feet per second.

Managed by the Oregon Water Resources Department, Chickahominy Reservoir is regulated and inspected regularly to ensure its safety and functionality. It features an uncontrolled spillway and needle outlet gates, with a significant hazard potential and moderate risk assessment. Despite its age, the dam's condition assessment remains unrated, highlighting the need for continued monitoring and maintenance to uphold its structural integrity and safeguard against potential risks to the surrounding community and environment.

Located in Harney County, Oregon, Chickahominy Reservoir serves as a vital water source for irrigation in the region, supporting agricultural activities and providing a reliable supply of water for local farmers. With its rich history and critical role in water management, this reservoir stands as a testament to the importance of sustainable water resource management and climate resilience in the face of changing environmental conditions.

Year Completed

1951

Dam Length

300

Dam Height

36

River Or Stream

CHICKAHOMINY CREEK

Primary Dam Type

Earth

Surface Area

529.4

Hydraulic Height

35

Drainage Area

28.2

Nid Storage

9000

Structural Height

38

Outlet Gates

Needle

Hazard Potential

Significant

Nid Height

38
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
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